Will We Recognize Intelligent Aliens when We Meet Them?

 Science fiction depicts many types of intelligent aliens. Often they are similar to humans, but with different, often bizarre, heads. However, most biologists believe that any aliens are unlikely to resemble humans at all. Life evolves due to the environmental conditions of the planet, and it is extremely unlikely that any other planet will have a geological and environmental history similar to Earth’s. With different conditions, intelligent life on those planets will take different forms compared to us humans.

Grey Aliens. Most commonly described by those who claim to have been abducted by aliens.

image by kjpargeter

But not all scientists agree with that idea. Simon Morris, a paleo-biologist with Cambridge University’s Department of Earth Sciences, believes, researchers that intelligent creatures similar to humans likely exist on many other planets.

Intelligent aliens are not likely to appear humanoid. From Star Trek Voyager

Non-humanoid alien. Created by Abiogenesis

Morris cites the theory of convergent evolution, which says intelligent species everywhere may evolve into something much like us. “One can say with reasonable confidence that the likelihood of something analogous to a human evolving is really pretty high. And given the number of potential planets that we now have good reason to think exist, even if the dice only come up the right way every 1 in 100 throws, that still leads to a very large number of intelligences scattered around, that are likely to be similar to us.”

As an example of this idea, Morris says that flight independently evolved at least four different times on Earth, in pterosaurs, birds, bats, and insects. Eyes, he says, evolved in different species perhaps as many as 40 times.

Many scientists strongly disagree with that idea. One of those is the late evolutionary biologist Stephen J Gould who found this idea utterly ridiculous. He claims that if you re-ran evolution on Earth, even given the same geological and environmental changes our planet endured, the likelihood of getting humans just like us is vanishingly remote. Since random environmental effects create random sets of genetic mutations, there is almost no possibility of ending up at the same evolutionary point. And imagining this evolution occurring on a distant planet with very different conditions compared to Earth is foolish.

Most scientists agree with Gould. And besides, if all intelligent life were just like, what a boring universe this would be.

  

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.Oklahoman.com.

Is There Life on Mars? Maybe, but We Haven't Looked in the Right Places

 Two new studies point to a real possibility of life on Mars. We know Mars once had lots of water, enough water to cover the entire planet by as much as three-quarters of a mile. That water is now lost from the surface.

                          Artist’s rendering of Mars before it lost surface water, credit NASA

One study, led by Eva Scheller, a planetary scientist at the California Institute of Technology, looked at the rate at which Mars lost water to space. Hydrogen, a component of water molecules, comes in various forms. Normal hydrogen consists of one proton and one electron. Deuterium, also called heavy hydrogen, also contains one neutron. Being heavier, deuterium can’t escape Mars as easily as normal hydrogen. By studying the ratio of the two, scientists can determine how much hydrogen, and therefore water, Mars lost to space since it formed. This allows the scientists to estimate the total amount of water Mars originally possessed.

Since the rate of hydrogen loss early in Mars’ history can’t be known precisely, scientists can only estimate the amount of water lost. They calculate that the total amount of water lost from Mars amounts to only enough to cover the planet by up to 82 feet. That leaves a lot of water still on Mars. The rest, they claim, went underground, chemically combined with minerals in the Martian crust. "Mars basically became the dry, arid planet we know today 3 billion years ago," Scheller stated. Since then, the amount of water locked below the crust has remained essentially unchanged. Water loss from Mars stopped when the remaining water became trapped in the crust.

                                                  Mars with polar ice cap, credit NASA

Nathalie Cabrol, director of the Carl Sagan Center for Research, part of the SETI Institute, led the second study. She claims life would still exist on Mars if it ever developed there. It simply would have moved underground with the water. We haven’t found it yet because we haven’t looked in the right places.

Cabrol studies some of the harshest environments on Earth, locations scientists refer to as Mars analogs. These places represent the environments on Earth most like Mars, a cold, dry desert world. She explains that at these locations on Earth, “You can walk on the same landscape for miles and find nothing. Then, maybe because the slope changes by a fraction of a degree, the texture or the mineralogy of the soil is different because there is more protection from UV, all of a sudden, life is here.”

On Earth, virtually everywhere water exists, so does life, even deep below ground with water trapped in rocks. Cabrol says that on Mars, other conditions must also be considered. “What matters in extreme worlds to find life is to understand the patterns resulting from these interactions.”

Both scientists agree that the Perseverance Rover, newly landed on Mars, may be able to find the right conditions for Martian life below the surface.

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

 This is reprinted by permission from the Oklahoman and www.newsok.com.

 

Alien Signals? Likely Not, But the Most Exciting Possibility Yet!

      Earth is a noisy planet. Not with sound waves, which never leave the atmosphere, but with all sorts of radio noise. Between radar beams from weather monitoring stations, airports and military use, TV and radio signals, and even deliberate attempts by astronomers to send messages to any listening aliens, our planet constantly announces its presence to the universe at large.

Because we are so radio noisy, astronomers have for decades tried to find such radio signals emanating from any other existing alien civilizations in our Milky Way, with little success. In 1977, astronomers performing such a search with a giant radio telescope run by Ohio State University detected a signal, a powerful radio burst, dubbed the “WOW!” signal. It never appeared again despite much searching.

In 2015, billionaire Yuri Milner donated $100M to create a program designed to search for extraterrestrial radio signals, the Breakthrough Listen Project. The project uses the Parke Radio Telescope in Australia, operated by the Commonwealth Scientific and Industrial Research Organization.

 Recently, news broke that the project detected a narrowly-focused beam of 980 MHz radio waves detected in April and May 2019. The signal came from the direction of our nearest stellar neighbor, Proxima Centauri, which has two planets orbiting it, and one is Earthlike. That frequency is important because human-made craft and satellites typically don’t use it, lending credence to the possibility of it coming from an alien civilization.

Parke Radio Telescope, credit Commonwealth Scientific and Industrial Research Organization

The powerful burst excited astronomers of the project. Sofia Sheikh, an astronomer at Penn State University, led the analysis of the signal. While the team has yet to release its full report, Scientific American interviewed Sheikh. She said, "It's the most exciting signal that we've found in the Breakthrough Listen project because we haven't had a signal jump through this many of our filters before.”

No repeat signal has been detected, and the team still must rule any natural signals, such as a distant comet or some other astronomical. But astronomers excitedly await the full report. We may have finally discovered that we have neighbors.

 

    Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

    This is reprinted by permission from the Oklahoman and www.newsok.com.

Are We Close to Finding Earth 2?

 

NASA and other space agencies have launched several missions to search for exoplanets, planets that orbit other stars. The Holy Grail of such programs is finding an Earth-like planet orbiting a sun-like star at the right distance to allow liquid water on the surface. Such planets seem to be the most likely candidates to search for life.

While astronomers have yet to find a perfect Earth 2, statistical analysis of NASA’s most successful planet hunter, the Kepler Mission, uncovered some promising data. A study by NASA scientists alongside collaborators from around the world who worked on the Kepler mission came to an exciting conclusion. According to the research, about half the stars similar in temperature to our Sun could have a rocky planet capable of supporting liquid water on its surface.

Image Caption/Credit: NASA’s Kepler Planet Finder telescope, credit NASA

"Kepler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable," said the lead author Steve Bryson, a researcher at NASA's Ames Research. "Though this result is far from a final value, and water on a planet's surface is only one of many factors to support life, it's extremely exciting that we calculated these worlds are this common with such high confidence and precision."

Kepler detected planets by continuously staring at thousands of stars, watching for a tell-tale drop in brightness caused by an orbiting planet crossing in front of a star. Such a method couldn’t detect planetary systems seen more face on, so astronomers had to use statistical methods to extrapolate from the Kepler data to all the other stars in our galaxy. Kepler discovered so many exoplanets from its limited mission that astronomers now believe that more than half of the four billion stars in the Milky planet possess planets, typically more than one.

Using their most conservative estimate, that 7% of all sun-like stars have Earth-like planets, meaning some 300 million exist in our Milky Way alone. Their most likely estimate states that Earth-like planets orbit 50% of sun-like stars, making more than 2 billion Earth-like planets. Since we know of only one planet with life, ours, those planets are the best place to begin to search for alien forms of life.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

 This is reprinted by permission from the Oklahoman and www.newsok.com.

Martian Life, if it Exists, Could Still Be Present Underground

 

Earth sits right in the middle of our sun’s habitable zone, the region where the heat of the star allows liquid water to exist on the surface of a planet. Mars orbits at the outer edge of this zone. Astronomers generally agree that Mars once sported rivers, lakes and, oceans. Mars reached such life-supporting conditions even before Earth. Its smaller size allowed it to cool more quickly from the heat of formation.

But Mars’ smaller size also allowed its core to cool and solidify long ago, killing its magnetic field. Without that magnetic field, solar radiation slowly knocked the atmosphere of Mars into space. Lacking an atmosphere, Mars couldn’t trap the sun’s heat, so it turned cold. Nighttime temperatures routinely drop to near 100 degrees below zero.

But, prior to the loss of its atmosphere, Mars sported conditions that could have supported life. That is no longer true of the surface of Mars. The thin atmosphere can no longer warm the surface of Mars nor protect it from cosmic radiation. Many scientists, including astrophysicist and research scientist Dimitra Atri, from the Center for Space Science at NYU Abu Dhabi, believe that conditions not far below the surface could potentially support life, albeit only at the bacterial level.

In 2022, the European Space Agency and Roscosmos, the Russian space organization, will launch the ExoMars craft, which includes the Rosiland Franklin rover. Atri says that rover will have the ability to detect any such subsurface life on the Red Planet. "It is exciting to contemplate that life could survive in such a harsh environment, as few as two meters (six feet) below the surface of Mars," said Atri. "When the Rosalind Franklin rover onboard the ExoMars mission, equipped with a subsurface drill, is launched in 2022, it will be well-suited to detect extant microbial life."

                           ExoMars Rosalind Franklin rover, Credit European Space Agency (ESA).

If we find life on Mars, it will indicate that life forms easily, given that life developed on both planets in our solar system capable of supporting it. That tells astronomers that perhaps many of the tens of billions of Earth-like planets in our Milky Way galaxy likely did, too.

     Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

     This is reprinted by permission from the Oklahoman and www.newsok.com.

Can Earth-like Exoplanets Actually Support Life?

As of July 4^th, the NASA Exoplanet Archive (https://exoplanetarchive.ipac.caltech.edu/) lists 4,183 confirmed exoplanets, planets orbiting other stars, with another 2089 candidate planets awaiting confirmation. NASA and other institutions have only studied a tiny percent of all the stars in our Milky Way. Based on the sample so far, astronomers estimate that planets outnumber stars in our galaxy. That means the Milky Way contains several hundred billion planets.

These exoplanets come in a bewildering variety. Some are Jupiter-sized planets so close to their parent star that the heat from the star evaporates them. Some Earth-sized planets get so hot, they rain liquid metal from their clouds. Most confirmed planets are significantly larger than Earth, but that’s because larger planets are easier to discover than smaller planets. Astronomer estimate that Earth-sized planets number in the billions.

   Most Earth-like Exoplanets, credit NASA

Being the size of Earth doesn’t mean such a planet has life on it. Many factors play into planet habitability. Distance to its parent star determines surface temperature. Too hot or too cold and habitability becomes unlikely. The type of parent star plays a crucial role. Stars smaller than our sun often produce large, dangerous stellar flares.

If Earth is a good example of what conditions necessary for a planet to support life, water is an absolute must. On our planet, where there’s water, life exists, even at the bottom of the ocean, with near-freezing temperatures, in boiling hot springs, or three miles underground in cracks in the rock.

Scientist Lynnae Quick along with several other NASA scientists looked at the likelihood of finding other life-bearing planets. This initial study contained a small sample of only 53 Earth-sized planets. They specifically looked to see if the planets could support surface or subsurface oceans, as is the case with several moons in our own solar system. Of those, they calculated that 30 likely possess such bodies of water, more than half of the planets they analyzed. With a few billion Earth-sized planets in our galaxy alone, that means there might be a lot of life-bearing planets out there. "Forthcoming missions will give us a chance to see whether ocean moons in our solar system could support life,” said Quick.

The study didn’t address the presence of intelligent aliens. There isn’t enough data to decide that. But at least we have some idea of the possibilities now.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

 This is reprinted by permission from the Oklahoman and www.newsok.com.

Life Below Earths Ocean Floor Give Scientists Hope for Finding Life on Mars

Ten years ago, scientists from the University of Tokyo, Japan, led an expedition to drill into rock 400 feet below the ocean floor. They have been studying the various rock samples, ranging in age from thirteen million years to 104 million years, ever since. Theses ocean rocks formed when undersea volcanoes spewed out lava which cooled into fractured rock and became buried under ocean sediment. The cracks filled with clays from the ocean floor.

The scientists knew that rocks beneath the surface of dry land were home to bacteria, and they looked for bacteria living in the ocean rocks. After intense study, with some missteps along the way, they finally found dense bacterial colonies, numbering more than 100 billion bacterial cells per cubic inch, living in the clay-filled cracks. This density of bacteria is similar to that found in the human gut. That compares to a paltry 1000 bacteria per cubic inch living in the muddy layers above the rock on the ocean floor.

"I thought it was a dream, seeing such rich microbial life in rocks," said Associate Professor Yohey Suzuki from the University of Tokyo, one of the leaders of the expedition. "Honestly, it was a very unexpected discovery. I was very lucky because I almost gave up."

This finding excites astrobiologists who search for signs of past, or present, life on Mars. Much of Mars was once covered by lakes and oceans, with similar clay minerals. Just as in the Earth study, Martian ocean sediments were eventually covered and compressed into rock at the bottom of those bodies of water.

"Minerals are like a fingerprint for what conditions were present when the clay formed. Neutral to slightly alkaline levels, low temperature, moderate salinity, iron-rich environment, basalt rock -- all of these conditions are shared between the deep ocean and the surface of Mars," said Suzuki.

Mars 2020 Rover Perseverance. Credit NASA

NASA will launch the next Martian rover, Perseverance, in late July or early August. Among other scientific instruments, Perseverance posses a biological testing lab that will search for similar bacterial colonies, living or fossilized, in similar Martian rock that was once the bottom of a Martian sea. The findings of Dr. Suzuki’s team gave NASA scientists the road map for searching for ancient, Martian bacterial colonies that may, perhaps, tell us that Mars was once, possibly still is, a home for life.

 Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.

Did NASA Already Find Martian Life?

In 1992, astronomers discovered three objects roughly the size of Earth orbiting another star, the first known exoplanets. No one expected life on those objects because the star was a pulsar, the remains of a star that blew up as a supernova, and the “planets” had actually formed from the debris of that explosion.

Three years later, astronomers found the first true exoplanets orbiting the sun-like star 51 Pegasi. Now, the NASA Exoplanet Archive lists 4113 confirmed exoplanets with more than 3600 exoplanet candidates awaiting confirmation. Astronomers believe that we have only touched the tip of the exoplanet iceberg. Data suggests that our Milky Way galaxy alone contains some two hundred billion planets. As of now, there’s no solid evidence suggesting that life exists on any of them.

But some scientists believe that we already found life on another planet, one much closer to home. In 1976, NASA landed twin spacecraft on Mars, Viking 1 and 2. Each included automated laboratories designed to search for microscopic life on the Red Planet.

Both craft, which landed 4000 miles apart, included a simple test called the Labeled Release experiment. It added a nutrient broth to a small amount of Martian soil and checked to see if any metabolic byproducts, like carbon dioxide, were released. Every test by both landers reported positive results. However, the other experiments on both landers found no organic chemicals, which seemed to preclude any lifeforms. Since then, most scientists decided that some odd chemistry in the Martian soil falsely mimicked those life signs.

Viking Lander, credit NASA

But not all scientists. Gilbert Levin was the principal investigator for the Labeled Release experiment for both landers. In a recent article in Scientific American, he wrote “The Viking LR (experiment) sought to detect and monitor ongoing metabolism, a very simple and fail-proof indicator of living microorganisms. Several thousand runs were made, both before and after Viking, with terrestrial soils and microbial cultures, both in the laboratory and in extreme natural environments. No false positive or false negative result was ever obtained. This strongly supports the reliability of the LR Mars data.”

It may be decades or centuries before we confirm life on an exoplanet, if we ever do. But we may have already discovered life on another planet, right next door.

There are Lots of Earth-like Planets -- How Many are Lifebearing?

Scientists who think about the possibility of extraterrestrial life need data to estimate those possibilities. Because Earth is the one and only known example of a life-bearing planet, it seems logical, therefore, to use ours as a model for life-bearing planets. The first, best place to hunt for alien life would be on planets like Earth

And this is where data is needed. Just how many Earth-like planets exist in our Milky Way galaxy? Fortunately, we have reams of data on planets orbiting other stars from the Kepler space telescope. It spent more than nine and a half years doing nothing but searching for extrasolar planets. It discovered more than 2,600 planets with nearly 3,000 still awaiting confirmation. That’s a lot of data.

One thing astronomers learned from a statistical analysis of that data is that Earth-like planets are rather common. Twenty billion sun-like stars call the Milky Way home, and Kepler teaches us that one in four of them have planets roughly the size of Earth orbiting in the habitable zone, where, as on Earth, liquid water can exist. That’s five billion Earth-like planets in the Milky Way. And that’s not even counting the billions of other stars of different sizes than our sun that also possess Earth-sized planets in their habitable zones.

Artist depiction of a habitable exoplanet. Credit NASA-JPL

That sure sounds like the potential exists for a galaxy teeming with life.

Now, astronomers want to check for the actual existence of alien life. We can’t yet send probes to examine those planets. But we can examine the atmosphere of an alien planet for life-supporting gases. According to Eric B. Ford, professor of astronomy and astrophysics at Penn State, “Scientists are particularly interested in searching for biomarkers – molecules indicative of life – in the atmospheres of roughly Earth-size planets that orbit in the ‘habitable zone’ of sun-like stars.”

With five billion planets to examine, the search might be tedious, but the payoff will be the most amazing scientific discovery ever. And it appears to be only a matter of time before we discover alien life.

The map shows the sky at 10:00 early in the month, 9:00 in the middle of the month, and 8:00 at the end of the month. Map produced using Night Vision star mapping software. 

On or about the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

Where is Everybody?

One summer day in 1950, physicists Enrico Fermi, leader of the team that built the first nuclear reactor, enjoyed lunch with several fellow physicists. Talk turned to recent UFO reports and the possibility of faster than light travel. Referring to aliens, Fermi suddenly blurted out "Don't you ever wonder where everybody is?" This question led to “The Fermi Paradox.”

Simply stated, if (as we now know) our galaxy contains billions of planets, many of them Earth-like, why haven’t we ever encountered any aliens? Earth is young, in cosmic terms. Many solar systems older than Earth exist, some billions of years older. If life existed on any of them, it would take no more than 50 million years to colonize the galaxy with the rocket technology being developed at that time, a blink of the eye in cosmic terms. So, Fermi wondered aloud, where is everybody?

Over the years, other scientists have suggested various answers.

Water is essential to life as we know it. Earth’s water exists on the surface, but for most of the other worlds in our solar system that possess oceans, four moons, the water is locked underground, below a frozen surface. That may be common for life-bearing planets or moons.

Many of the planets we’ve discovered that could have water are classified as super-Earths, planets up to ten times larger than Earth. The gravity of such planets may well make space travel impossible.

Futurist and astronomer Seth Shostak, says that all intelligent aliens may actually be intelligent machines. We ourselves are on the verge of creating such machines and, within a few thousands of years, all intelligence on Earth may be machine-based, not biological.

Some scientists suggest that alien life may be so different from us, we’d never recognize it. Or, perhaps just as we destroy ants without even realizing it when building a house, maybe all other life forms have been eradicated. Or they wiped themselves out with climate change.

Maybe we have met the aliens and they are us. The “panspermia hypothesis” says life was seeded on Earth by comets (or alien spacecraft?), making us the very aliens we search for.

Even so, we need to keep looking.

From NASA's search for extraterrestrial life. Credit NASA-HST

On or about the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.

Water on Mars from Deep Groundwater Sources

In 2015, NASA announced the discovery of water flowing down the sides of craters on Mars. NASA calls them Reoccurring Slope Lineae, RSL for short. This seemed to answer the question of whether liquid water currently existed on Mars. And since liquid water is believed to be a prime requirement for life, the discovery also reinvigorated the discussion of life, even if only microscopic, on the red planet. You can see a NASA video montage of some RSLs at https://youtu.be/H44-XrGH5IQ.

Reoccurring Slope Lineae on Mars, credit NASA

In 2017, some researchers published papers suggesting RSLs were not from water but consisted of sand sliding down the slopes, driven by carbon dioxide that sublimated from dry ice just below the surface. Carbon dioxide, being a relatively heavy gas, flows downhill and carries sand grains with it. The researchers suggested that the sand just below the surface might be darker, having not been bleached by UV radiation from the sun.

The consensus of scientific opinion, however, rested with water flow, but many wondered if water just below the surface of the cold planet could never melt. Recently, Essam Heggy, a research scientist at the University of Southern California and NASA's Jet Propulsion Laboratory, and Abotalib Z. Abotalib, a postdoctoral research associate at USC, suggested that the flows are triggered not by near-surface water but rather from deep below the surface. "We propose an alternative hypothesis, that they originate from a deep, pressurized groundwater source, which comes to the surface, moving upward along ground cracks," said Hegggy.

They compared Martian geological features to similar ones on Earth and determined that heat flow in the Martian subsurface was similar to that in desert regions here on Earth. This research, the two concluded, indicates that RSL water is probably coming from deeply buried, briny aquifers.

This even explains the seasonal aspect of the flows. "The system shuts down during winter seasons, when the ascending near-surface water freezes within fault pathways, and resumes during summer seasons when brine temperatures rise above the freezing point," the researchers wrote.

The new study says nothing about the existence of life on Mars, but it will surely strengthen arguments for at least microbial Martians living below the surface.

       On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

      This is reprinted by permission form the Oklahoman and www.newsok.com.

Our Nearest Potentially Habitable Cosmic Neighbor

According to NASA’s Exoplanet web page (exoplanetarchive.ipac.caltech.edu/index.html), we know of 3,779 planets orbiting stars other than our sun, with 2,737 more candidates awaiting confirmation. And that is just the tip of the exoplanet iceberg.

The large majority of confirmed and suspected exoplanets are discovered by the transit method. A telescope in space or on Earth stares at a star and watches for small drops in the light output that indicate a planet is passing in front of, or transiting, the star. There are many ways a star’s light may vary, but each has a specific signature as to how the brightness varies. Planetary transits cause a unique alteration in the star’s light.

This method can only detect planets whose orbit lies along our line of sight, and that’s quite unlikely. That astronomers have found so many exoplanets when they can only detect such a tiny fraction of potential candidates implies a huge number of exoplanets exist. In fact, astronomers estimate based on the known sample that the 400 billion stars in the Milky Way average 1.3 planets each.

That’s a lot of planets.

It turns that that one exoplanet is literally right next door. The closest star system to us is Alpha Centauri. It actually consists of three stars. Two of them, Alpha Centauri A and B, both roughly the size of our sun, orbit each other rather closely. The third member, named Proxima Centauri, orbits those two in a wide, 550,000-year orbit. Proxima comes closer to us than any other star, 4.2 light years at its closest.

Proxima is known to possess a planet only slightly larger than earth. And the planet lies in the star’s habitable zone, where the star provides enough heat to allow liquid water, as on Earth. Since Proxima is a red dwarf star, much smaller than our sun, the planet must orbit close to the star to be warm enough. The planet’s orbit takes only 11 days. But it is exactly in the middle of Proxima’s habitable zone. Being so close to the parent star, it is probably tidally locked. One side constantly faces the star, just like only one side of the Moon always faces Earth. This means one side is in constant daylight, the other perpetual night.

Artist conception of Proxima Centauri b - credit NASA

Anthony Del Genio, a planetary scientist at the NASA Goddard Institute for Space Studies, led a group of scientists doing computer simulations on Proxima b. They wanted to know if the planet could support life. They made the reasonable assumptions that the planet had an atmosphere as thick as Earth’s and enough water to form an ocean. Using computer models like those used by researches to study climate change on Earth, they found that under a broad range of conditions, the planet can sustain liquid water even on the night side. On Earth, where there’s water, there’s life. “The major message from our simulations is that there’s a decent chance that the planet would be habitable,” said Del Genio.

Our nearest habitable neighbor may literally orbit our nearest stellar neighbor.

On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission form the Oklahoman and www.newsok.com.